The present invention relates to substituted thiophenesulfonamide compounds, to herbicidal compositions containing the compounds, and to the utility of the compounds for the control of unwanted vegetation.
The control of unwanted vegetation by means of chemical agents, i.e., herbicides, is an important aspect of modern agriculture and land management. While many chemicals that are useful for the control of unwanted vegetation are known, new compounds that are more effective generally, are more effective for specific plant species, are less damaging to desirable vegetation, are safer to man or the environment, are less expensive to use, or have other advantageous attributes are desirable.
Many substituted benzenesulfonamide compounds are known and certain of them are known to possess herbicidal activity. For example, certain N-([1,2,4]triazolo[1,5-a]pyrimidin-2-yl)benzenesulfonamide compounds and their herbicidal utility were disclosed in U.S. Pat. No. 4,638,075 and certain N-([1,2,4]triazolo[1,3,5]triazin-2-yl)benzenesulfonamide compounds were disclosed in U.S. Pat. No. 4,685,958. In addition, certain N-([1,2,4]triazolo[1,5-c]pyrimidin-2-yl)benzenesulfonamide, N-([1,2,4]triazolo[1,5-c]pyrimidin-2-yl)pyridinesulfonamide, N-([1,2,4]triazolo[1,5-a]pyridin-2-yl)benzenesulfonamide, and N-([1,2,4]triazolo[1,5-a]pyridin-2-yl)pyridinesulfonamide compounds were disclosed in U.S. Pat. No. 5,858,924. Certain N-phenyl arylsulfonamide compounds are also known and are known to possess herbicidal activity. For example, certain N-(substituted phenyl)[1,2,4]triazolo[1,5-c]pyrimidin-2-sulfonamide compounds were disclosed in U.S. Pat. No. 5,163,995 and certain N-(substituted phenyl)[1,2,4]triazolo[1,5-a]pyridin-2-sulfonamide compounds were disclosed in U.S. Pat. No. 5,571,775.
It has now been found that a class of novel N-(triazoloazinyl)thiophenesulfonamide compounds comprising N-([1,2,4]triazolo[1,5-c]pyrimidin-2-yl)thiophenesulfonamide, N-([1,2,4]triazolo[1,5-a]pyrimidin-2-yl)thiophenesulfonamide, and N-([1,2,4]triazolo[1,5-a]pyridin-2-yl)thiophenesulfonamide compounds are potent herbicides for the control of unwanted vegetation by either preemergence or post-emergence application. The invention includes N-(triazoloazinyl)thiophenesulfonamide compounds of Formula I: 
wherein
X represents CH or
Y represents CZ or N with the proviso that X and Y are not both N;
W represents H or OR with the proviso that when Y is CZ, then W is H;
Z represents R, OR or halo;
D and E represent S or CB with the proviso that one of D or E is S;
A and B independently represent H, halo, CF3, R, ORxe2x80x2 or CO2Rxe2x80x3;
T represents H, SO2Rxe2x80x3, C(O)Rxe2x80x3, C(O)ORxe2x80x3, C(O)NRxe2x80x32, or CH2CH2C(O)ORxe2x80x3;
R represents CH3 or CH2CH3;
Rxe2x80x2 represents C1-C4 alkyl, C3-C4 alkenyl, or C3-C4 alkynyl each optionally possessing up to two chloro, bromo or O(C1-C4)alkyl substituents or up to the maximum possible number of fluoro substituents;
Rxe2x80x3 represents H or C1-C4 alkyl;
and, when T represents H, the agriculturally acceptable salts thereof.
Compounds wherein A represents ORxe2x80x2 or B represents CO2Rxe2x80x3 when D represents S and T represents H are among the preferred compounds of the invention.
The invention further includes compositions containing herbicidal amounts of compounds of Formula I in combination with one or more agriculturally acceptable adjuvants or carriers and the use of the compounds of Formula I as herbicides. The use of suitable compounds of the invention to achieve total vegetation control is generally preferred. Both grassy and broadleaf weeds can be controlled. Post-emergence application of the compounds to undesirable vegetation is generally preferred.
The N-(triazoloazinyl)thiophenesulfonamide compounds of the invention can generally be described as substituted N-([1,2,4]triazolo[1,5-c]pyrimidin-2-yl)thiophenesulfonamide, N-([1,2,4]triazolo[1,5-a]pyrimidin-2-yl)thiophenesulfonamide, and N-([1,2,4]triazolo[1,5-a]pyridin-2-yl)thiophenesulfonamide compounds. They can be characterized as substituted thiophenesulfonamide compounds possessing, on the amide nitrogen atom, a substituted [1,2,4]triazolo[1,5-c]pyrimidin-2-yl, a substituted [1,2,4]triazolo[1,5-a]pyrimidin-2-yl or a substituted [1,2,4]triazolo[1,5-a]pyridin-2-yl moiety.
The herbicidal compounds of the invention are N-(triazoloazinyl)thiophenesulfonamide compounds of generic Formula I: 
Such compounds in which X represents N contain a substituted N-([1,2,4]triazolo[1,5-c]pyrimidin-2-yl) moiety, those in which Y represents N contain a substituted N-([1,2,4]triazolo[1,5-a]pyrimidin-2-yl) moiety and those in which X represents Cxe2x80x94H and Y represents Cxe2x80x94Z contain a substituted N-([1,2,4]triazolo[1,5-a]pyridin-2-yl) moiety. Compounds in which E represents S are 2-thiophenesulfonamide compounds and compounds in which D represents S are 3-thiophenesulfonamide compounds. The compounds are further characterized by possessing a methoxy or an ethoxy substituent adjacent to the bridgehead nitrogen in the 6-membered ring portion of the triazoloazine ring and by possessing at least one substituent (A) adjacent to the sulfonamide on the thiophene ring.
The compounds of the invention include compounds of Formula I wherein X is N or CH.
Compounds in which X is N are often preferred. However, compounds in which X is CH are sometimes preferred.
The compounds of the invention include compounds of Formula I wherein Y is N, provided that X is not also N, or CZ in which Z is methyl, ethyl, methoxy, ethoxy or halo. Compounds in which Y is CZ are often preferred. However, compounds in which Y is N are sometimes preferred. Compounds in which Z is methoxy are often preferred.
Compounds of the invention include compounds of Formula I wherein D and E represent S or CB, provided that one and only one of D or E is S. The thiophene-3-sulfonamides in which D represents S are usually preferred.
Compounds of the invention include compounds of Formula I wherein A and B independently represent H, halo, CF3, R, ORxe2x80x2 or CO2Rxe2x80x3. A is preferably ORxe2x80x2 or CO2Rxe2x80x3, and most preferably ORxe2x80x2.
Compounds of the invention include compounds of Formula I wherein W represents H or OR provided that when Y is CZ, W is H. When Y is N, W is preferably methoxy.
For compounds of the present invention, R can be CH3 or CH2CH3. For OR, R is preferably CH3.
For compounds of the present invention, Rxe2x80x2 can be C1-C4 alkyl, C3-C4 alkenyl, or C3-C4 alkynyl each optionally possessing up to two chloro, bromo or O(C1-C4)alkyl substituents or up to the maximum possible number of fluoro substituents. For ORxe2x80x2, Rxe2x80x2 is preferably C1-C4 alkyl optionally possessing up to two chloro, bromo or O(C1-C4)alkyl substituents or up to the maximum possible number of fluoro substituents.
The compounds of Formula I include those wherein T represents hydrogen, an alkylsulfonyl group (SO2Rxe2x80x3), an acyl group (C(O)Rxe2x80x3), an alkoxycarbonyl group (C(O)ORxe2x80x3), an aminocarbonyl group (C(O)NRxe2x80x32), or a 2-(alkoxycarbonyl) ethyl group (CH2CH2C(O)ORxe2x80x3). Such compounds wherein T represents hydrogen are preferred. The invention further includes the agriculturally acceptable salts of compounds of the Formula I wherein T represents hydrogen.
For compounds of the present invention, Rxe2x80x3 can be H or C1-C4 alkyl. Rxe2x80x3 is preferably CH3 or CH2CH3.
Compounds of Formula I which possess each possible combination of preferred, more preferred, most preferred, desirable, and special interest substituents are, further, considered to be important embodiments of the invention.
The terms alkyl, alkenyl, and alkynyl (including when modified as in haloalkyl and alkoxy) as used herein include straight chain, branched chain, and cyclic groups. Thus, typical alkyl groups are methyl, ethyl, 1-methylethyl, propyl, 1,1-dimethylethyl and cyclopropyl. Methyl and ethyl are often preferred. Alkyl groups are sometimes referred to herein as normal (n), iso (i), secondary (s) or tertiary (t). Typical alkyl with up to the maximum possible number of fluoro substituents include trifluoromethyl, monofluoromethyl, 2,2,2-trifluoroethyl, 2,3-difluoropropyl, and the like; trifluoromethyl is often preferred. The term halogen includes fluorine, chlorine, bromine, and iodine.
The term xe2x80x9cagriculturally acceptable saltsxe2x80x9d is employed herein to denote compounds wherein the acidic sulfonamide proton of the compound of Formula I is replaced by a cation which itself is neither herbicidal to crop plants being treated nor significantly deleterious to the applicator, the environment, or the ultimate user of any crop being treated. Suitable cations include, for example, those derived from alkali or alkaline earth metals and those derived from ammonia and amines. Preferred cations include sodium, potassium, magnesium, and aminium cations of the formula:
R2R3R4NH+
wherein R2, R3, and R4 each, independently represents hydrogen or (C1-C12)alkyl, (C3-C12)cycloalkyl, or (C3-C12)alkenyl, each of which is optionally substituted by one or more hydroxy, (C1-C8)alkoxy, (C1-C8)alkylthio or phenyl groups; provided that R2, R3, and R4 are sterically compatible. Additionally, any two of R2, R3 and R4 together may represent an aliphatic difunctional moiety containing 1 to 12 carbon atoms and up to two oxygen or sulfur atoms. Salts of the compounds of Formula I can be prepared by treatment of compounds of Formula I wherein V represents hydrogen with a metal hydroxide, such as sodium hydroxide, potassium hydroxide or magnesium hydroxide, or an amine, such as ammonia, trimethylamine, hydroxyethylamine, bisallylamine, 2-butoxyethylamine, morpholine, cyclododecylamine or benzylamine.
The compounds of Table 1 and 2 are examples of the compounds of the invention. Some of the specifically preferred compounds of Formula I, which vary depending on the weed species to be controlled, the crop present (if any), and other factors, include the following compounds of Table 1 and 2: N-(5,8-dimethoxy[1,2,4]triazolo[1,5-c]pyrimidin-2-yl)-4-methoxythiophene-3-sulfonamide and N-(5,8-dimethoxy[1,2,4]triazolo[1,5-c]pyrimidin-2-yl)-2-carboxymethylthiophene-3-sulfonamide.
The compounds of Formula I wherein T represents hydrogen can be prepared by the reaction of a substituted 2-amino[1,2,4]triazoloazine compound of Formula II: 
with a thiophenesulfonyl chloride compound of Formula III: 
wherein A, D, E, R, W, X and Y are as defined for compounds of Formula I. The reaction can be carried out by combining approximately equal molar amounts of the two compounds in a polar, aprotic solvent, such as acetonitrile, and adding pyridine and a catalytic amount (5 to 25 molar percent of the sulfonyl chloride compound) of dimethyl sulfoxide at room temperature. Additional sulfonyl chloride compound, pyridine, and dimethyl sulfoxide are added, if necessary, to complete the reaction. The reactions take from a few hours to several days to go to completion. Means to exclude moisture, such as a dry nitrogen blanket, are employed. The compounds of Formula I obtained, which are solids with low solubility in many common organic solvents and in water, can be recovered using conventional means.
N-(triazoloazinyl)thiophenesulfonamide compounds of Formula I wherein T represents other than hydrogen can be prepared from the corresponding compounds of Formula I wherein T represents hydrogen by acylation under reaction conditions known in the art for related sulfonamide acylation reactions. Suitable acylating agents include alkanoyl chloride compounds, such as propionyl chloride or trifluoroacetyl chloride; chloroformate ester compounds, such as 2-methoxyethyl chloroformate; carbamoyl chloride compounds, such as Nxe2x80x2,Nxe2x80x2-diallylcarbamoyl chloride, and alkyl isocyanate compounds, such as 2-chloroethyl isocyanate.
Compounds of Formula I having alkoxy substituents in the triazoloazine ring can be prepared from the corresponding halo compounds of Formula I by treatment with an appropriate alkoxide using the general methods for such replacements known in the art. Halo substituents in some positions are generally more easily replaced than are halo substituents in other positions depending on the triazoloazine ring system and can be selectively replaced.
Many 2-amino[1,2,4]triazolo[1,5-a]pyridine compounds of Formula II (X represents Cxe2x80x94H and Y represents Cxe2x80x94Z) can be prepared by the reaction of appropriately substituted N-(2-pyridinyl)-Nxe2x80x2-carboethoxythiourea compounds of the formula: 
wherein Z is as defined for compounds of Formula I and L is OR or halo, with hydroxylamine. The reaction is typically carried out in a solvent such as ethanol and requires heating for a few hours. The hydroxylamine is typically generated by neutralization of the hydrochloride with a hindered tertiary amine, such as diisopropylethylamine, or an alkali metal alkoxide, such as sodium ethoxide. The desired compounds of Formula II can be recovered by conventional means, such as by removal of the volatile components of the reaction mixture by evaporation, and can be purified by conventional means, such as by extraction with water and/or other solvents in which they are sparingly soluble. The N-(2-pyridinyl)-Nxe2x80x2-carboethoxythiourea compound starting materials for this method can be obtained by treatment of appropriately substituted 2-aminopyridine compounds with ethoxycarbonyl isothiocyanate. The reaction is generally carried out in an inert organic solvent at ambient temperatures. The overall method is further described in U.S. Pat. No. 5,571,775.
The substituted 2-aminopyridine compound starting materials for the method described above are known in the art or can be prepared by the methods disclosed herein or by general methods known in the art.
Compounds of Formula II wherein X represents Cxe2x80x94H can also be prepared from appropriately substituted 2-cyanoaminopyridine compounds by the method disclosed by B. Vercek et al. in Monatshefte fur Chemie, 114, 789-798 (1983). Additional methods of preparation of such compounds were disclosed by K. T. Potts et al. in Journal of Organic Chemistry, 31, 265-273 (1966).
Compounds of Formula II wherein X represents N, i.e., 2-amino[1,2,4]triazolo[1,5-c]pyrimidine compounds, can be prepared from 4-hydrazinopyrimidine compounds of the formula: 
wherein Q represents methylthio or chloro and Z is as defined for compounds of Formula I. The hydrazinopyrimidine compound is first treated with cyanogen bromide to produce the hydrobromide of a 3-amino-8-substituted-5-substituted[1,2,4]triazolo[4,3-c]pyrimidine compound of the formula: 
wherein Q represents methylthio or chloro and Z is as defined for compounds of Formula I. The reaction is generally carried out in an organic solvent, such as isopropyl alcohol, at ambient temperature. The products can be recovered by conventional means, such as by adding a non-polar solvent, for example diethyl ether, and collecting the solid that forms by filtration. The above intermediates wherein Q represents methylthio can then be converted into the desired compounds of Formula II wherein Q represents an alkoxy group by treatment with an alkali metal alcoholate, such as sodium methylate or potassium ethylate, and ethyl acrylate in the corresponding alcohol as a solvent. The compound rearranges and the methylthio moiety is replaced by the alkoxy moiety derived from the alcohol of the medium. The reaction is generally carried out at temperatures below 25xc2x0 C. The desired compounds of Formula II can be recovered by neutralizing with acetic acid and collecting the solids that form by filtration or other conventional means. Compounds of Formula II wherein X represents N and Q represents chloro can be obtained from the corresponding [4,3-c] intermediate wherein Q represents chloro by isomerization with a trialkylamine base. The 4-hydrazinopyrimidine compound starting materials for these methods can be prepared from the corresponding 4-chloropyrimidine compounds, which are well-known in the art, by reaction with hydrazine.
Other methods of preparation of compounds of Formula II wherein X represents N are disclosed by G. W. Miller, et al., J. Chemical Society, 1965, page 3357 and 1963, page 5642.
Compounds of Formula II wherein Y represents N, e.g., 2-amino[1,2,4]triazolo[1,5-a]pyrimidine compounds, can be prepared by the reaction of N-(4,6-dialkoxypyrimidin-2-yl)-Nxe2x80x2-carboethoxythiourea of the formula: 
wherein R is as defined for Formula I with hydroxylamine. The reaction is typically carried out in a solvent such as ethanol and requires heating for a few hours. The hydroxylamine is typically generated by neutralization of the hydrochloride with a hindered tertiary amine, such as diisopropylethylamine, or an alkali metal alkoxide, such as sodium ethoxide. The desired compound of Formula II can be recovered by conventional means, such as by removal of the volatile components of the reaction mixture by evaporation, and can be purified by conventional means, such as by extraction with water and/or other solvents in which they are sparingly soluble. The N-(4,6-dialkoxypyrimidin-2-yl)-Nxe2x80x2-carboethoxythiourea starting material for this method can be obtained by treatment of 2-amino-4,6-dialkoxypyrimidine with ethoxycarbonyl isothiocyanate. The reaction is generally carried out in an inert organic solvent at ambient temperatures. The overall method is further described in U.S. Pat. No. 5,571,775.
The 2-amino-4,6-dialkoxypyrimidine starting material for the method described above is known in the art.
The substituted thiophenesulfonyl chloride starting materials of Formula III can be prepared by the methods disclosed herein or by general or specific methods known in the art. Many such compounds can be prepared by lithiation of the corresponding thiophene compound with butyl lithium, reaction of the thienyl lithium compound obtained with SO2, and then chlorination with N-chlorosuccinimide. In each of these reaction steps, conditions generally known for such processes were used. Thienyl lithium compounds can also be prepared by halogen-metal exchange reactions of halothiophenes with n-butyl lithium. Many propyl or benzylthiothiophenes can also be prepared by alkylation of the corresponding mercaptothiophene compound using standard methods or by reaction of the thienyl lithium compounds with the appropriate disulfide. Subsequent chloroxidation with, for example, chlorine in the presence of water provides the desired sulfonyl chlorides.
Compounds of Formula III include substituted thiophene-2-sulfonyl chloride compounds of the formula: 
and substituted thiophene-3-sulfonyl chloride compounds of the formula: 
wherein A and B independently represent H, halo, CF3, R, ORxe2x80x2 or CO2Rxe2x80x3. The substituted thiophene-3-sulfonyl chlorides are preferred, particularly those in which A or B are ORxe2x80x2 or CO2Rxe2x80x3.
While it is possible to utilize the N-(triazoloazinyl)thiophenesulfonamide compounds of Formula I directly as herbicides, it is preferable to use them in mixtures containing an herbicidally effective amount of the compound along with at least one agriculturally acceptable adjuvant or carrier. Suitable adjuvants or carriers should not be phytotoxic to valuable crops, particularly at the concentrations employed in applying the compositions for selective weed control in the presence of crops, and should not react chemically with the compounds of Formula I or other composition ingredients. Such mixtures can be designed for application directly to weeds or their locus or can be concentrates or formulations that are normally diluted with additional carriers and adjuvants before application. They can be solids, such as, for example, dusts, granules, water dispersible granules, or wettable powders, or liquids, such as, for example, emulsifiable concentrates, solutions, emulsions or suspensions.
Suitable agricultural adjuvants and carriers that are useful in preparing the herbicidal mixtures of the invention are well known to those skilled in the art.
Liquid carriers that can be employed include water, toluene, xylene, petroleum naphtha, crop oil, acetone, methyl ethyl ketone, cyclohexanone, trichloroethylene, perchloroethylene, ethyl acetate, amyl acetate, butyl acetate, propylene glycol monomethyl ether and diethylene glycol monomethyl ether, methanol, ethanol, isopropanol, amyl alcohol, ethylene glycol, propylene glycol, glycerine, N-methyl-2-pyrrolidinone, and the like. Water is generally the carrier of choice for the dilution of concentrates.
Suitable solid carriers include talc, pyrophyllite clay, silica, attapulgus clay, kieselguhr, chalk, diatomaceous earth, lime, calcium carbonate, bentonite clay, Fuller""s earth, cotton seed hulls, wheat flour, soybean flour, pumice, wood flour, walnut shell flour, lignin, and the like.
It is frequently desirable to incorporate one or more surface-active agents into the compositions of the present invention. Such surface-active agents are advantageously employed in both solid and liquid compositions, especially those designed to be diluted with carrier before application. The surface-active agents can be anionic, cationic or nonionic in character and can be employed as emulsifying agents, wetting agents, suspending agents, or for other purposes. Typical surface active agents include salts of alkyl sulfates, such as diethanolammonium lauryl sulfate; alkylarylsulfonate salts, such as calcium dodecylbenzenesulfonate; alkylphenol-alkylene oxide addition products, such as nonylphenol-C18 ethoxylate; alcohol-alkylene oxide addition products, such as tridecyl alcohol-C16 ethoxylate; soaps, such as sodium stearate; alkylnaphthalenesulfonate salts, such as sodium dibutylnaphthalenesulfonate; dialkyl esters of sulfosuccinate salts, such as sodium di(2-ethylhexyl) sulfosuccinate; sorbitol esters, such as sorbitol oleate; quaternary amines, such as lauryl trimethylammonium chloride; polyethylene glycol esters of fatty acids, such as polyethylene glycol stearate; block copolymers of ethylene oxide and propylene oxide; and salts of mono and dialkyl phosphate esters.
Other adjuvants commonly utilized in agricultural compositions include compatibilizing agents, antifoam agents, sequestering agents, neutralizing agents and buffers, corrosion inhibitors, dyes, odorants, spreading agents, penetration aids, sticking agents, dispersing agents, thickening agents, freezing point depressants, antimicrobial agents, and the like. The compositions can also contain other compatible components, for example, other herbicides, herbicide safeners, plant growth regulants, fungicides, insecticides, and the like and can be formulated with liquid fertilizers or solid, particulate fertilizer carriers such as ammonium nitrate, urea and the like.
The concentration of the active ingredients in the herbicidal compositions of this invention is generally from about 0.001 to about 98 percent by weight. Concentrations from about 0.01 to about 90 percent by weight are often employed. In compositions designed to be employed as concentrates, the active ingredient is generally present in a concentration from about 5 to about 98 weight percent, preferably about 10 to about 90 weight percent. Such compositions are typically diluted with an inert carrier, such as water, before application. The diluted compositions usually applied to weeds or the locus of weeds generally contain about 0.001 to about 5 weight percent active ingredient and preferably contain about 0.01 to about 0.5 percent.
The present compositions can be applied to weeds or their locus by the use of conventional ground or aerial dusters, sprayers, and granule applicators, by addition to irrigation water, and by other conventional means known to those skilled in the art.
The compounds of Formula I have been found to be useful preemergence (including pre-plant) and postemergence herbicides. Postemergence applications are generally preferred. The compounds are effective in the control of both broadleaf and grassy weeds. While each of the N-(triazoloazinyl)thiophenesulfonamide compounds encompassed by Formula I is within the scope of the invention, the degree of herbicidal activity, crop selectivity, and spectrum of weed control obtained varies depending upon the substituents and other features present. The compounds can be employed at higher, non-selective rates of application to control essentially all of the vegetation in an area. In some cases, the compounds can also be employed at lower, selective rates of application for the control of undesirable vegetation in grass crops or in broadleaf crops. In some instances, the selectivity can often be improved by the use of safeners.
The term herbicide is used herein to mean an active ingredient that controls or adversely modifies the growth of plants. An herbicidally effective or vegetation controlling amount is an amount of active ingredient which causes an adversely modifying effect and includes deviations from natural development, killing, regulation, desiccation, retardation, and the like. The terms plants and vegetation are meant to include germinant seeds, emerging seedlings and established vegetation.
Herbicidal activity is exhibited by the compounds of the present invention when they are applied directly to the plant or to the locus of the plant at any stage of growth or before planting or emergence. The effect observed depends upon the plant species to be controlled, the stage of growth of the plant, the application parameters of dilution and spray drop size, the particle size of solid components, the environmental conditions at the time of use, the specific compound employed, the specific adjuvants and carriers employed, the soil type, and the like, as well as the amount of chemical applied. These and other factors can be adjusted as is known in the art to promote non-selective or selective herbicidal action. Generally, it is preferred to apply the compounds of Formula I postemergence to relatively immature plants to achieve the maximum control of weeds.
Application rates of about 0.001 to about 1 Kg/Ha are generally employed in postemergence operations; for preemergence applications, rates of about 0.01 to about 2 kg/ha are generally employed. The higher rates designated generally give non-selective control of a broad variety of undesirable vegetation. The lower rates typically give selective control and, by judicious election of compounds, timing, and rates of application, can be employed in the locus of crops.
The compounds of the present invention (Formula I) are often applied in conjunction with one or more other herbicides to obtain control of a wider variety of undesirable vegetation. When used in conjunction with other herbicides, the presently claimed compounds can be formulated with the other herbicide or herbicides, tank mixed with the other herbicide or herbicides, or applied sequentially with the other herbicide or herbicides. Some of the herbicides that can be employed beneficially in combination with the compounds of the present invention include substituted triazolopyrimidinesulfonamide compounds, such as diclosulam, cloransulam-methyl and flumetsulam. Other herbicides such as acifluorfen, bentazon, chlorimuron, clomazone, lactofen, carfentrazone-methyl, fumiclorac, fluometuron, fomesafen, imazaquin, imazethapyr, linuron, metribuzin, fluazifop, haloxyfop, glyphosate, glufosinate, 2,4-D, acetochlor, metolachlor, sethoxydim, nicosulfuron, clopyralid, fluroxypyr, metsulfuron-methyl, amidosulfuron, tribenuron, and others can also be employed. It is generally preferred to use the compounds in conjunction with other herbicides that have a similar crop selectivity. It is further usually preferred to apply the herbicides at the same time, either as a combination formulation or as a tank mix.
The compounds of the present invention can generally be employed in combination with a wide variety of known herbicide safeners, such as cloquintocet, mefenpyr, furilazole, dichlormid, benoxacor, flurazole, fluxofenim, daimuron, dimepiperate, thiobencarb, and fenclorim, to enhance their selectivity. Herbicide safeners that act by modifying the metabolism of herbicides in plants by enhancing the activity of cytochrome P-450 oxidases are usually especially effective. This is often a preferred embodiment of the invention. The compounds can additionally be employed to control undesirable vegetation in many crops that have been made tolerant to or resistant to herbicides by genetic manipulation or by mutation and selection. For example, crops that have been made tolerant or resistant to herbicides in general or to herbicides that inhibit the enzyme acetolactate synthase in sensitive plants can be treated.